Boron-Doped Graphene Quantum Dots (BGQDs) from Spent Coffee Ground for Glucose Sensor

Figure 6

(a) The XPS wide scan of GQDs and BGQDs (b–h) are C1s, N1s, O1s, and B1s of GQDs and BGQDs, respectively.

(a)

(b)

(c)

(d)

(e)

(f)

(g)

(h)